COMMONWEALTH 375 Imperial Constitution, to extend the work of the Statute of Westminster, and define the position of Mother Country and Dominions more precisely. Reluctance to dissect a relation which seems to rest more on feeling than on material facts, has so far prevented progress in this direction. Differences of opinion which now lie hid might be brought to the surface by the search for exact definition. Some machinery of Imperial administration has, however, proved necessary and usefiil. Each Dominion maintains in Britain a High Commissioner, whose relations with the Dominions OflBce resemble those of an Ambassador with the Foreign Office. It is further the business of the High Com- missioner's Staff to set before the people in Britain the economic possibilities of the Dominions, and to encourage trade, investment and migration. There are also the Imperial Conferences which have been held at irregular intervals since 1907. Britain is represented by the Prime Minister, who presides, and by the Secretaries for the Dominions and for India; Prime Ministers and other representatives of the Dominions attend. The agenda is settled by previous communication, and has contained matters relating to foreign policy and defence, Dominion status, and trade. In 1932 a special Imperial Economic Conference was held at Ottawa. Decisions were reached which have had great effect on the policy of Britain and of the Dominions. The immediate cause of the conference was the shrinkage of world trade, and consequent unemployment. There emerged a series of agreements, by which Britain and the Dominions mutually agreed to grant preferences to each other's products—i.e., to impose tariffs on foreign goods, and lesser tariffs or none at all, on goods from other British countries. The Colohial Empire was also affected by these decisions; preferences for goods from Great Britain entering the Colonies were now extended to goods from the Dominions, and the importation of foreign goods by the Colonies was restricted. The Ottawa Conference succeeded in enlarging inter-Imperial trade, and its decisions were welcome at a time when trade of any kind was slight. The States of the world having failed to achieve a